Heat the oven to 225°F.
Line two large baking sheets with parchment paper.
Slice the cucumbers into 1/8-inch rounds.
Sprinkle 1/4 teaspoon of the salt over the slices.
Let them sit on paper towels for 15 minutes.
Blot both sides very well until the surface looks dry.
Toss the slices with olive oil, garlic powder, onion powder, pepper, and remaining salt.
Arrange them in a single layer on the baking sheets.
Bake for 1 hour and 15 minutes.
Flip each slice, rotate the pans, and keep baking 45 to 75 minutes.
Pull the crisp ones as they’re ready.
Cool the batch for 10 minutes so they firm up more.